Saving the Wine by Means of Acid Removal

Good news for winemakers is that thanks to new technology, volatile acid may now be removed from wine that would otherwise have to be wasted or distilled.

Excessively high volatile acid imparts a vinegary character to wine and for this reason, legal limits were instituted world-wide regarding the permissible level of volatile acid in wine. In South Africa this limit is 1,2 g per litre. Bacteriological activities before, during or after fermentation may result in excessive volatile acid.

As far as could be ascertained, two undertakings are currently capable of removing volatile acid and apparently they have saved literally millions of litres of wine that may have been ruined by volatile acid.

They are VA Filtration and Envigoration, both of which use mobile units to tie in with the seasonal requirements at cellars.

VA Filtration is a partnership between a chemical engineer, a filtration industry expert and winemaker Hardy Laubser. They have been operational since August last year and already almost 1,5 million litres of wine have been processed, thus building a solid client base.

They use an advanced filtration process to remove volatile acid from the wine and have just patented their process . which has always been permissible, according to Hardy. “Our process is very gentle and specifically removes only the volatile acid from the wine without disturbing any of the other components.”

The other undertaking, Envigoration (a process engineering company from Paarl), collaborated with Nicky Krone of Twee Jonge Gezellen in Tulbagh, Dr Johan Marais of Nietvoorbij and counterparts in America and Australia, where the technique is already being practised. They have since patented their technique in South Africa.

Envigoration has done much experimental work on various cultivars. The process, namely reverse osmosis, has just been approved on an experimental commercial basis by the Wine and Spirits Board.

Although this technique is prohibited in the European Union, it is considered acceptable cellar practice in Switzerland and the New World wine countries. In South Africa it was not permissible for a long time, but the Wine and Spirits Board reinvestigated the matter last year.

They requested Winetech, the wine industry’s co-ordinating research body, to make all available data about the effect of the process available and indicate whether they believe this process may be considered a normal cellar practice. Winetech’s recommendation was in favour of it.

The removal of volatile acid from wine by means of reverse osmosis may therefore be added to the list of “undesirable flavours” in Table 7 of the regulations issued in terms of the Liquor Products Act No 60 of 1989, which makes provision for substances that may be removed from liquor products.

“We give winemakers peace of mind,” says Nicky Krone. In the past wine with a high volatile acidity could be distilled, but the distilled wine market no longer exists. “Our goal is definitely not to support bad oenology, but to come to the rescue when isolated slip-ups ruin valuable wines. Winemakers should remember that our process cannot turn a bad wine into a good one, it rather restores valuable wines.”

“Politically we have always tried to remain in Europe’s good books, but meanwhile New World wine countries such as America and Australia are applying this new technology. We should be careful not to be such purists that we cause our own downfall.

“We should remember furthermore that our climatological conditions differ drastically from those of Europe. Their wine countries are cold and they have low pH and high acid, with the result that bacteria do not develop as quickly. In South Africa we can make the Dolly Parton wines demanded by the rest of the world, soft, rounded, easily accessible and fruity, but that requires a specific risk from the winemaker. Our technology gives South African winemakers the opportunity to make optimal use of our climate, but if something does go wrong, they have the opportunity to rectify the matter.”

Both undertakings do not foresee treating millions of litres of wine per annum, but reather seasonal activity when winemakers experience more problems with volatile acid due to weather conditions which cause the grapes to ripen too fast.